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Background. Ferulic acid esterases (FAE, EC 3.1.1.73), also known as feruloyl esterases, cinnamic acid esterases or cinnamoyl esterases, belong to a common group of hydrolases distributed in the plant kingdom. Especially the fungal enzymes were very well characterised in the past whereas the enzyme was rarely found in the lactic acid bacteria (LAB) strains. It is well known that strong antioxidants free phenolic acids can be released from the dietary fiber by the action of intestinal microflora composed among others also of Lactobacillus strains. The aim of this study was to examine four Lactobacillus strains (L. acidophilus KI, Z,, rhamnosus E/N, PEN, OXY) for the ability to produce extracellular FAE on different synthetic and natural carbon sources. Material and methods. The LAB strains were grown in the minimal growth media using German wheat bran, rye bran, brewers’ spent grain, isolated larchwood arabinogalactan, apple pectin, com pectin, methyl ferulate, methyl p-coumarate, methyl syringate or methyl vanillate as the sole carbon source. FAE activity was determined using the postcultivation supematants, methyl ferulate and F1PLC with UV detection. Results. The highest FAE activity was obtained with L. acidophilus KI and methyl ferulate (max. 23.34 ±0.05 activity units) and methyl p-coumarate (max. 14.96 ±0.47 activity units) as carbon sources. L. rhamnosus E/N, OXY and PEN exhibited the limited ability to produce FAE with cinnamic acids methyl esters. Methyl syringate and methyl vanillate (MS and MV) were insufficient carbon sources for FAE production. Brewers’ spent grain was the most suitable substrate for FAE production by L. acidophilus KI (max. 2.64 ±0.06 activity units) and L. rhamnosus E/N, OXY and PEN. FAE was also successfully induced by natural substrates rye bran, com pectin (L. acidophilus KI), German wheat bran and larchwood arabinogalactan (E/N, PEN) or German wheat bran and com pectin (OXY). Conclusions. This study proved the ability of Lactobacillus strains to produce FAE in the presence of a wide rangę of different ester-bound substrates. The highest enzyme activities obtained in the presence of synthetic phenolic acids methyl esters suggest that the bacteria were forced to produce FAE whereas in the presence of natural substrates other carbon sources were exploited. FAE is the enzyme of the minor importance during the de- composition of the food matrix during the intestinal absorption but the further characterisation of these enzymes should be carried on.
Background. Lactic acid bacteria (LAB) were pointed out to produce ferulic acid es- terase. Except the release of phenolic acids front esterified forms, it was postulated that the biotransformations of these compounds can occur during the bacterial growth. In the presented work, the biotransformation of ferulic acid by Lactobacillus acidophilus KI and three Bifidibacterium strains (B. animalis Bi30, B. catenulatum KD 14 and B. longum KN 29) was studied. Material and methods. The microorganisms were grown in media containing methyl esters of phenolic acids as carbon sources. The feruloyl esterase activity as well as the contents of phenolic acids in supematants were estimated using HPLC-DAD. Results. The enzyme activity was evaluated using methyl ferulate exclusively, but p- -coumaric acid and another chromatographic peak (probably caffeic acid, but its identity was not positively confirmed by the DAD analysis) were present in reaction mixtures containing the supematants of Lactobacillus acidophilus KI cultivars with methyl p-coumarate or methyl syringate. Both peaks of p-coumaric acid and another phenolic compound were also present in the Solutions containing the supematants of B. catenulatum and B. longum grown in the presence of methyl vanillate and the supematants of B. animalis Bi30 grown using methyl p-coumarate, methyl syringate or methyl vanillate. Conclusions. The results suggest a distinct ability of the studied LAB strains to transform free ferulic acid yielding p-coumaric acid and probably caffeic acid although no mechanism involved in this transformation was proposed and closer characterised in the frames of this work.
It is commonly believed that gall inducers have the ability to control and program the host plant growth to their own benefit. The pattern of changes in the contents of reducing sugars, protein and phenolic compounds as well as the activity of chitinase and β-1,3-glucanase in galls, galled and intact leaves of Ulmus pumila were investigated during three stages of Tetraneura ulmi gall development. High protein accumulation in galls at the initial period of gall formation, increased biosynthesis of total phenolics during galling process, and the highest activity of pathogenesis-related protein at the stage of mature galls were detected. Therefore, it can be suggested that T. ulmi can manipulate the biochemical machinery of the galls for its own needs.
Nutritional and nutraceutical quality of sprouts is strongly affected by growth conditions. This study focused on determining the influence of breeding density on seedling growth, phenolics content and some antioxidant capacity of ready-to-eat lentil sprouts. Content of condensed tannins (ranging from 1.77 to 3.16 mg g-1 DM) and flavonoids (ranging from 15.13 to 25.08 mg g-1 DM) increased with the increasing density of breeding. The contents of the p-hydroxybenzoic and ferulic acids, and (+) catechin decreased with the increasing density of breeding in 3-days-old seedlings. Additionally, the level of quercetin was elevated at a higher degree in sprouts cultivated at density of 1.22 seeds per cm2 and average 10.42 and 5.91 ȝg g-1 DM for 3- and 4-days-old sprouts, respectively. Metal chelating ability was the highest for sprouts obtained at the lowest density: 92% and 86% for 3- and 4-days-old sprouts, respectively. Fresh mass yield and lipids preventing abilities were negatively affected by density of breeding. It can be concluded that density of breeding plays an important role in design of chemical composition and bioactivity of lentil sprouts.
Owies i produkty owsiane są ważnym źródłem tłuszczów, błonnika pokarmowego, sacharydów, składników mineralnych, witamin oraz białka. Hydroliza enzymatyczna białek prowadzi do uwalniania peptydów, które mogą wykazywać różnorodną aktywność, w tym przeciwutleniającą. Przeprowadzone badania miały na celu określenie właściwości przeciwutleniających hydrolizatów białek owsa uzyskanych z 12 odmian (genotypów) uprawnych i dzikich heksa- i tetraploidalnych gatunków z rodzaju Avena L. Izolat białkowy (IBO9) otrzymany z ziaren dzikiej formy owsa należącej do gatunku A. maroccana CN 43136 charakteryzował się największą liczbą polimorficznych frakcji białkowych. Ponadto hydrolizat HBO9 otrzymany z białek ziaren owsa A. maroccana CN 43136 wykazywał najwyższą zdolność do neutralizacji wolnych rodników generowanych z ABTS (87,27 %) oraz DPPH (46 %). Natomiast największą zdolność do chelatowania jonów Fe (II) – 90,12 %, oznaczono w HBO7 (A. sterilis AVE 2116), forma dzika. Stwierdzono, że krzyżowanie międzygatunkowe podwyższa właściwości przeciwutleniające hydrolizatów białek owsa, a w konsekwencji korzystnie wpływa na właściwości prozdrowotne ziarna.
Nowadays, legume plants have been considered not only a source of valuable proteins necessary for the proper functioning and growth of the body but also a source of bioactive compounds such as bioactive peptides, that may be beneficial to human health and protect against negative change in food. The aim of this study was to investigate the effect of heat treatment on the release of antioxidant peptides obtained by hydrolysis of the yellow string beans protein. The antioxidant properties of the hydrolysates were evaluated through free radical scavenging activities (DPPH and ABTS) and inhibition of iron activities (chelation of Fe2+). The results show that the heat treatment had influence on both increased peptides content and antioxidant activity after pepsin hydrolysis of string bean protein. The peptides content after protein hydrolysis derived from raw and heat treated beans were noted 2.10 and 2.50 mg ml-1, respectively. The hydrolysates obtained from raw (PHR) and heat treated (PHT) beans showed better antioxidant properties than protein isolates (PIR and PIT). Moreover, the hydrolysates obtained from heat treated beans showed the higher ability to scavenge DPPH' (46.12%) and ABTS+' (92.32%) than obtained from raw beans (38.02% and 88.24%, correspondingly). The IC50 value for Fe2+ chelating ability for pepsin hydrolysates obtained from raw and heat treatment beans were noted 0.81 and 0.19 mg ml-1, respectively. In conclusion, the results of this study showed that the heat treatment string beans caused increase in the antioxidant activities of peptide-rich hydrolysates.
Pietruszka zwyczajna (Petroselinum crispum Mill) jest wykorzystywana jako surowiec w przemyśle spożywczym m.in. ze względu na dużą zawartość związków fenolowych. W niniejszej pracy badano wpływ rozpuszczalników na skład oraz wybrane biologiczne właściwości ekstraktów z liści P. crispum. Porównano ekstrakty: wodny (W), etanolowy (ET), glikolowo-wodny (GLW) i glicerolowo-wodny (GCW). Największą zawartość związków fenolowych ogółem oznaczono w ekstraktach GLW (2,63 ± 0,03 mg/g s.m.) i GCW (2,12 ± 0,08 mg/g s.m.), natomiast najwięcej flawonoidów zawierał ekstrakt ET (0,86 ± 0,02 mg/g s.m.). Głównymi związkami fenolowymi ekstraktu wodnego były: epikatechina, katechina i jej pochodne, ekstraktu etanolowego – kwasy fenolowe (np. rozmarynowy), ekstraktu GLW – apigenina, natomiast ekstraktu GCW – daidzeina, naryngenina i pochodne. Oprócz znacznych różnic w składzie ilościowym i jakościowym badanych ekstraktów wykazywały one także zróżnicowaną aktywność przeciwrodnikową. Ekstrakt GCW w największym stopniu neutralizował rodnik DPPH• (IC₅₀ = 6,89 ± 056 μg/ml), natomiast ekstrakt W – kationorodnik ABTS•+ (IC₅₀ = 31,44 ± 4,11 μg/ml). Wszystkie ekstrakty wykazywały porównywalną zdolność do chelatowania jonów Fe²⁺. W badaniu cytotoksyczności ekstraktów w warunkach in vitro w stosunku do ludzkiej linii komórkowej BJ (ATCC CRL-2522) wykazano najwyższą cytotoksyczność ekstraktów ET i W. Cytotoksyczność ekstraktów GLW i GCW była porównywalna z cytotoksycznością samych rozpuszczalników. Dowiedziono wpływu rozpuszczalników na skład, właściwości przeciwutleniające oraz cytotoksyczność ekstraktów z P. crispum, wskazując równocześnie na możliwość zastosowania tych ekstraktów w przemyśle spożywczym.
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